The present invention relates to apparatus for supplying paper sheets or the like to one or more processing or consuming machines, and more particularly to improvements in apparatus for diverting groups of partially overlapping sheets to one or more machines which process discrete sheets, sections of or entire newspapers, brochures or the like.
It is already known to utilize a transporting system which receives sheets from a printing press or another suitable source and advances the sheets in the form of a scalloped stream to one or more processing or consuming machines, such as gathering machines and the like. As a rule, the transporting system includes switches which can be actuated to divert portions of the stream into a consuming machine whenever the need arises, e.g., when the magazine of a particular consuming machine is empty or the supply of sheets therein is about to be depleted. The transporting system is normally associated with a group forming device which breaks up a continuous stream of partly overlapping sheets into a file of discrete groups each of which contains a predetermined number of sheets. The width of clearances or gaps between neighboring groups of the file suffices to insure that the diversion of an entire preceding group from the main path can be completed and the switch returned to normal position before the foremost sheet of the next-following group reaches the diverting station.
In the event of malfunction of a consuming or processing machine (e.g., a machine which assembles different types of sheets into signatures or the like and delivers signatures to a collating machine), the group of sheets which was destined to be admitted into the defective or intentionally arrested consuming machine continues to advance along the main path which is defined by the transporting system and enters a stacker (also called overflow) which is located at the discharge end of the transporting system. In most instances, the cause of malfunction is eliminated within a short interval of time. However, and since each malfunction of a consuming machine involves the advancement of at least one complete group of partially overlapping sheets into the stacker, the latter is likely to rapidly accumulate a substantial supply of sheets, i.e., a high percentage of sheets is or is likely to be withdrawn from immediate processing.
Another drawback of presently known transporting systems is that, when a conventional system serves to deliver groups of sheets to several processing or consuming machines which are disposed one after the other, as considered in the direction of transport of groups of sheets, a consuming machine which is remote from the source of sheets cannot immediately receive one or more groups of sheets when the need for replenishment of the supply of sheets in such consuming machine arises. This will be readily appreciated by bearing in mind that the admission of sheets to a consuming machine invariably involves the diversion of at least one complete group of sheets from the main path which is defined by the transporting system. Thus, and assuming that a preceding consuming machine receives one or more groups of sheets, the stream of sheets in the main path exhibits one or more wide gaps which develop as a result of removal of one or more complete groups; therefore, a remote consuming machine is likely to process the entire supply of sheets in its magazine before a group of sheets which follows a wide gap in the main path reaches that switch which must be actuated to divert one or more groups into the magazine of the remote consuming machine. Furthermore, a switch cannot be moved while a group of sheets advances therealong toward the next consuming machine or to the stacker. This further aggravates the situation because the just mentioned group must advance beyond the switch and the latter moves to a different position in order to divert one or more groups into the remote consuming machine with a corresponding delay. The delay is further increased if the group which has advanced beyond the just mentioned switch is followed by a relatively wide gap resulting from diversion of one or more groups into the preceding consuming machine or machines. It happens quite frequently that a remote consuming machine will use up the entire supply of sheets in its magazine before the transporting system delivers a fresh supply (one or more groups) of sheets.